The use of proteolytic enzymes (proteases) in animal feed is well known, as for example from the following documents:
WO95/28850 discloses an animal feed additive comprising a phytase and a proteolytic enzyme. Various proteolytic enzymes are specified at p. 7.
WO96/05739 discloses an enzyme feed additive comprising xylanase and a protease. Suitable proteases are listed at p. 25.WO95/02044 discloses proteases derived from Aspergillus aculeatus, as well as the use in animal feed thereof.
U.S. Pat. No. 3,966,971 discloses a process of obtaining protein from a vegetable protein source by treatment with an acid phytase and optionally a proteolytic enzyme. Suitable proteases are specified in column 2.
Vitamin C refers to a number of vitamers that have vitamin C activity in animals, including ascorbic acid and its salts, and some oxidized forms of the molecule like dehydroascorbic acid.
Vitamin C or L-ascorbic acid or simply ascorbate is required for a range of essential metabolic reactions in all animals and plants. Ascorbate is not synthesized by humans and some species of birds and fish. On the other hand, ascorbate or vitamin C is made internally by almost all farm animals. Animals, as for example pigs and poultry, are fully capable of synthesizing enough vitamin C (ascorbic acid) to meet normal daily needs.
This is the reason why under commercial conditions vitamin C is not used as feed additive in regular animal diets. Vitamin C is added to animal diets only in exceptional cases, as for example to poultry diets to combat heat stress and to pig diets during periods of stress (early weaning).
Surprisingly, the inventors of the invention found that the addition of a proteolytic enzyme (protease) to regular animal diets results in a significant improvement of growth performance if the proteolytic enzyme is supplemented and combined with vitamin C.